Various solutions to the problem of determining the position and orientation of mobile equipment units have been previously proposed. Solutions invariably take advantage of a variety of localization sensors, including some of those given above.
Duddek et al. (1992) discloses a method of determining the position and orientation of the end of a excavator bucket utilising GPS sensors and a receiver in the vicinity of the bucket wheel.
Kalafut et al. (2002) proposes a system by which the position and heading of a machine can be determined through the use of a single positioning sensor. Readings are taken from the positioning sensor over time, and a motion profile is generated to estimate the heading of the machine. This approach is particularly applicable to machines that are commonly in motion, and have well-defined dynamic characteristics. In a mining application, haul trucks are a good candidate for this type of approach, so long as they are in motion.
Another example of a single-sensor positioning system is that proposed by Sahm et al. (1995) which uses a single sensor, capable of collecting (x, y, z)-position measurements connected to the boom of a mining shovel. If the shovel's undercarriage is assumed to be stationary during a dig cycle, then a set of points can be measured over time to generate the plane in which the sensor exists. This estimate, along with the current measurement of position from the sensor, can be used to estimate the current position of the shovel bucket.
The method of localizing from an estimated plane is further explored by Dizchavez (2001). Two GPS antennas are mounted on the machine house at known locations of equal elevation. During the operation of the machine, rotation of the house can be measured, and using calculations based on standard-deviation analysis, an estimate of the plane in which the two antennas lie is formed. From this plane, and the current position and orientation of the sensors within the plane, another part of the machine can be localized given a kinematic model and appropriate joint position information.
It is desirable to provide an improved method and apparatus for determining the spatial pose of mining equipment or the like.
Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.
Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.